The present invention relates to a system for charging an electric vehicle, a corresponding electric vehicle and a method for charging an electric vehicle.
For reasons of environmental protection as well as cost, options are being sought today to reduce the fuel consumption and thus the pollutant emissions of vehicles.
On option for reducing the fuel consumption of a vehicle is the use of a hybrid drive or an electric drive. Such vehicles can, for example, be charged at an electric outlet prior to a trip and be driven by an electric drive until the electrical energy store is empty.
In order to charge the energy store of such vehicles, charging stations are usually used today, which, e.g., can be installed in a house or the garage of an owner of the vehicle. Such charging stations can, however, also be set up at locations that are accessible to the public, e.g., parking lots. A vehicle owner can thus charge the energy store of his/her vehicle while he/she is shopping or at work. The energy store can thereby be charged via a charging cable with AC or DC current or, e.g., in a contactless manner by means of inductive energy transmission. A charging output of 3.5 kW is typically available.
The German patent application DE 20 2011 103 003 U1 demonstrates, for example, a possible form of a charging station for conductive AC current charging with the aid of a charging cable.
When charging such a vehicle, the vehicle is typically only charged via an individual phase of the energy supply network which is configured as a three-phase supply.
In unfamiliar areas, it is not always easy for owners to find a suitable charging station for their vehicle. In order to simplify the search for a charging station, so-called electric mobility service providers, also referred to simply as “providers”, can assist the driver of the respective vehicle in finding an open charging station. The providers can also, in certain circumstances for a fee, reserve a charging station for the owner of the vehicle.
When looking for a charging station, the provider can, e.g., provide an application that is operated on a smartphone of the driver or on an infotainment system of the vehicle. The application can, e.g., via a telematics system of the vehicle, e.g. a GPS receiver, detect the position of the vehicle and lead the driver to the charging station.
The network level 7 of the energy supply network is usually designed as a three-phase system (e.g. 230/400 V). If a multiplicity of charging stations are now coupled to this three-phase system, the single-phase charging stations are on a statistical average usually evenly distributed over the three phases.
It can however not be excluded that a multiplicity of vehicles in a network of the network level 7 is connected to precisely those charging stations which are connected to the same phase of the three-phase supply network.
This leads to an asymmetrical load on the supply network which can lead to a breakdown of the network of the network level 7 or of the low-voltage transformer of the network level 6.
At a charging station, the driver of a vehicle is not able to recognize to what extent a load is already applied to that phase to which his/her vehicle is coupled by means of the respective charging station.